Bag-in-box film form packaging refrigerated liquids

ABSTRACT

Multi-layer films for making bags for containing flowable materials, in particular to large bags for dairy products. The multi-layer films have an outer and an inner sealant layer and a core layer and optionally, an interposed layer positioned between the outer sealant layer and the core layer and between the core layer and the inner sealant layer. The outer and inner sealant layers contain an ethylene/a-olefin interpolymer composition and the intermediate layer optionally contains this interpolymer composition.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/523,433 filed Jun. 22, 2017, the entirety of which is incorporated byreference herein for any and all purposes.

FIELD OF THE INVENTION

This invention relates to ethylene polymer based multi-layer films usedto form bags for flowable liquid products that have improved bagtoughness particularly under chilled condition, e.g. 0-10° C. asmeasured by a bag drop test wherein a liquid filled bag is dropped froma set height.

BACKGROUND

In one aspect, the present invention relates to packaging flowableliquid products, such as, dairy products in bags for bag in boxpackaging, Typically, such bags are made using bag forming equipmentwherein rolls of film are unwound to form a bag that is labeled with acode via inkjet printer and the bag is punched to form a hole for thespout and the spout is inserted and the bag is sealed on the long sidesand usually brushed to remove air and then cross sealed at the bottom ofone bag and at the top of the next bag being made and pulled through theline and perforated adjacent to the cross seals and packaged for use ona bag in box filling line.

For reasons of economy, customers are demanding thinner films for bagsfor liquid products. This often leads to problems in commerciallyavailable films such as, (1) inadequate seal strength and toughnessparticularly as measured by a bag drop test wherein a liquid filled bagis dropped from predetermined heights. Reduction in bag performance hasbeen noted in the dairy industry, in particular, for bags that arefilled with chilled or refrigerated dairy products and moreparticularly, relative large bags, e.g., 1-6 gallon bags and larger.Such dairy product filled bags made from currently commerciallyavailable films, bag performance decreases significantly as thetemperature is lowered. This is particularly noted under when exposed totemperature changes and handling under shipment and distribution andresults in issues of leakage of such bags due to tears and breaks inseals of the bag, primarily is side and bottom seals and around thespout of the bag.

The multilayer film utilized in the present invention provides anexcellent bag for dairy products, in particular, large bag in the boxdairy products. The film is tough and durable and withstands lowtemperatures and temperature changes occurring during shipping andhandling and essentially eliminates tears and breaks in seals of thebags which result in leakage. The film contains an ethylene/α-olefininterpolymer compositions as disclosed in U.S. Pat. 9,115,275 issuedAug. 25, 2015 that is hereby incorporated by reference hereinafter “US9,115,275”.

SUMMARY OF THE INVENTION

The present invention relates to a number of multi-layer films formaking bags for containing flowable materials. Basically, thesemulti-layer films have an outer and an inner sealant layer and a corelayer and optionally, an interposed layer positioned between the outersealant layer and the core layer and between the core layer and theinner sealant layer. The outer and inner sealant layers contain anethylene/α-olefin interpolymer composition and the interposed layerpreferably contains this interpolymer composition.

It should be noted that each layer, such as the sealant layer, can havemultiple layers such as 2, 3, 4, 5 and the like and the outer sealantlayer and inner sealant layer can be the same or each have a differentnumber of layers, e.g., the outer sealant layer can have four layerswhile the inner sealant layer can have 2 layers. Similarly, theinterposed layer between the core and the outer sealant layer can have adifferent number of layers in comparison to the interposed layer betweenthe core and inner sealant layer. The core can have a number of layersand need not be a single layer.

The ethylene/α-olefin interpolymer composition comprises from 50-75% byweight of a first ethylene/a-olefin copolymer fraction having a densityin the range of 0.894 to 0.908 g/cc; a melt index in the range of 0.2 to1 g/10 min. and from 25 to 50 percent by weight of a secondethylene-α-olefin copolymer fraction and wherein the interpolymer has adensity in the range of 0.910 to 0.924 g/cc and a melt index in therange from 0.5 to 2 g/10 min; a zero shear viscosity ratio (ZSVR) in therange of from 1.15 to 2.5; a molecular weight distribution., expressedas the ratio of the weight average molecular weight (Mw/Mn) in the rangeof 2.0 to 4.0, and tan delta at 0.1 radian/ seconds and 190° C. in therange of 6 to 43 and as further described in US 9,115.575 and will bereferred to hereinafter as “ethylene/α-olefin interpolymer”.

The ethylene/α-olefin interpolymer composition is further defined as acomposition having 2 peaks on elution profile via crystallizationelution fractionation (CEF) procedure, wherein each peak comprises atleast 25 weight percent of the total area of the elution profile,wherein the separation of the 2 peak positions are in the range of from20 to 40° C., wherein a higher elution temperature peak is at an elutiontemperature greater than 90° C., and wherein a lower elution temperaturepeak is at an elution temperature in the range of from 50 to 80° C., andwherein the width of the higher elution temperature peak at 50 percentpeak height is less than 4° C., and wherein the width of the higherelution temperature peak at 10 percent peak height is less than 9° C.,and wherein the width of the lower elution temperature peak at 50percent peak height is less than 8° C., and wherein the width of thelower elution temperature peak at 10 percent height is less than 25° C.

A preferred ethylene/α-olefin interpolymer composition comprises apolymer fraction of a LLDPE (linear low density polyethylene) and asecond copolymer fraction of ethylene/octene -1 copolymer and theinterpolymer having a density of 0.915 g/cc. and a melt index of 0.85g/10 min.: herein after “preferred ethylene/α-olefin interpolymer”.

The following show multilayer structures that illustrate the invention:

A multilayer structure that comprises at least three layers of:(Structure 3 & 4)

(1) an outer and an inner sealant layer comprising the preferredethylene/α-olefin interpolymer. As pointed out above the outer and innersealant layers may be multiple layers and need not be identical in thenumber of layers and total thickness of the sealant layer.

(2) a core layer of LLDPE (linear low density polyethylene),ethylene/octene -1 copolymer having a melt index of 1.0 g/10 min. anddensity of 0.916 g/cc. (“Elite 5400G). The core layer may be singlelayer or multiple layers, e.g., 2-8 layers;

Alternatively, the core layer may comprise 30-100% by weight of LLDPE,ethylene/octene -1 copolymer having a melt index of 1.0 g/10 min. anddensity of 0.916 g/cc. (“Elite 5400G) and 70-0% by weight of LLDPE,ethylene/butene copolymer having a melt index of 1.0 g/10 min. and adensity of 0.918 g/cc. Preferably, the copolymers can be in a weightratio of 40/60.

An additional alternative core layer may comprise 30-100% by weight ofLLDPE, ethylene/hexene -1 copolymer having a melt index of 1.0 g/10 min.and density of 0.916 g/cc. (“Elite 5400G) and 70-0% by weight of LLDPE,ethylene/hexene copolymer having a melt index of 1.0 g/10 min. and adensity of 0.918 g/cc.(DFDC 7087) . Preferably, the copolymers can be ina weight ratio of 40/60.

Another aspect of this invention is directed to multilayer film havingthe following structure: (Structure 9)

(1) an inner and an outer sealant layer comprising ULDPE (ultra-lowdensity polyethylene), ethylene/octene -1 copolymer having a melt indexof 0.85 g/10 min. and density of 0.912 g/cc. (“Elite AT 6401 ) and anethylene/α-olefin interpolymer, for example, LLDPE. ethylene/octene-1copolymer having a melt index of 0.85 g/10 min. and density of 0.920g/cc (XUS 59900.100);

(2) an interposed layer of the preferred ethylene/α-olefin interpolymer.

(3) a core layer of LLDPE, ethylene/octene -1 copolymer having a meltindex of 1.0 g/10 min. and density of 0.916 g/cc. (“Elite 5400G).

Alternatively, the core layer may comprise 30-100% by weight of LLDPE,ethylene/octene -1 copolymer having a melt index of 1.0 g/10 min. anddensity of 0.916 g/cc. (“Elite 5400G) and 70-0% by weight of LLDPE,ethylene/butene copolymer having a melt index of 1.0 g/10 min. and adensity of 0.918 g/cc.(DFDC 7087). Preferably, the copolymers can be ina weight ratio of 40/60.

An additional alternative core layer may comprise 30-100% by weight ofLLDPE, ethylene/hexene -1 copolymer having a melt index of 1.0 g/10 min.and density of 0.916 g/cc. (“Elite 5400G) and 70-0% by weight of LLDPE,ethylene/hexene copolymer having a melt index of 1.0 g/10 min. and adensity of 0.918 g/cc.(DFDC 7087). Preferably, the copolymers can be ina weight ratio of 40/60.

Still other aspects of the invention include multilayer films of variouscombinations of the above mentioned layers. An important aspect of themultilayer film is that at least the outer and inner layers contain thepreferred ethylene/α-olefin interpolymer or an intermediate layer cancontain the preferred ethylene/α-olefin interpolymer or the inner andouter layer and intermediate layer contain the preferredethylene/α-olefin interpolymer. Optionally, it may be desirable for thecore to contain a fraction of the preferred interpolymer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a general schematic of a multi-layer film of the presentinvention.

DESCRIPTION OF THE INVENTION Definitions and Terms

All percentages expressed in the present patent application are byweight of the total weight of the composition unless expressedotherwise.

All ratios expressed in this patent application are on a weight: weightbasis unless expressed otherwise.

Ranges are used as shorthand only to avoid listing and describing eachand every value within the range. Any appropriate value within the rangecan be selected as the upper value, the lower value, or the end-point ofthe range.

The singular form of a word includes its plural, and vice versa, unlessthe context clearly dictates otherwise. Thus, references “a,” “an,” and“the” generally include the plurals of the respective terms theyqualify. For example, reference to “a method” includes itsplural-“methods.” Similarly, the terms “comprise,” “comprises.” and“comprising,” whether used as a transitional phrase in the claims orotherwise, should be interpreted inclusively rather than exclusively.Likewise the terms “include,” “including,” and “or” should be construedto be inclusive, unless such a construction is clearly prohibited fromthe context. Similarly, the term “examples,” particularly when followedby a listing of terms, is merely exemplary and illustrative and shouldnot be deemed to be exclusive or comprehensive.

Methods, compositions, and other advances disclosed in this patentapplication are not limited to particular methodology, protocols, andreagents described in the application because, as the skilled artisanwill appreciate, they may vary. Further, the terminology used in thisapplication describes particular embodiments only, and should not beconstrued as limiting the scope of what is disclosed or claimed.

Unless defined otherwise, all technical and scientific terms, terms ofart, and acronyms used in the present application have the meaningscommonly understood by one of ordinary skill in the art in the field(s)of the invention, or in the field(s) where the term is used. Althoughany compositions, methods, articles of manufacture, or other means ormaterials similar or equivalent to those described in the present patentapplication can be used in the practice of the present invention,specific compositions, methods, articles of manufacture, or other meansor materials are described only for exemplification.

All patents, patent applications, publications, technical and/orscholarly articles, and other references cited or referred to in thispatent application are incorporated in their entirety by reference tothe extent allowed by law. The discussion of those references isintended merely to summarize the assertions made in these references. Noadmission is made that any such patents, patent applications,publications or references, or any portion thereof, are relevant,material, or prior art. The right to challenge the accuracy andpertinence of any assertion of such patents, patent applications,publications, and other references as relevant, material, or prior artis specifically reserved.

As used herein, the term “flowable material” does not include gaseousmaterials powders or other solid materials, but encompasses liquidmaterials which are flowable under gravity or may be pumped. Suchmaterials include liquids, for example, milk, water, fruit juice, oil;emulsions, for example, ice cream mix, soft margarine. The inventiondescribed herein is particularly useful for flowable foods such as milkespecially packaged at refrigerated temperatures.

As used herein “density” is determined by ASTM D 792 and “melt-index” byASTM D 1238. The “melting point” of a polymer is measured as the peakmelting point when performing differential scanning calorimetry (DSC) asdescribed in ASTM Procedure D3417-83 (rev. 88).

In particular, this invention relates to multi-layer films usable forbags for packaging liquid flowable materials, typically dairy products.More specifically, this invention provides a multi-layer film that islower in gauge (thickness) but exhibits superior toughness and sealstrength, especially under refrigerated conditions as shown by higherbag drop heights (F50 values) as measured by the Bruceton staircase bagdrop test method.

In one embodiment, the multi-layer film comprises five layers (FIG. 1 ):a first outer sealant layer and an inner sealant layer (5) of thepreferred ethylene/α-olefin interpolymer; a second interposed layer (2)of the preferred ethylene/α-olefin interpolymer and a third layer (3)being a core layer of a core layer of LLDPE, ethylene/octene -1copolymer having a melt index of 1.0 g/10 min. and density of 0.916g/cc. (“Elite 5400G) and LLDPE, ethylene butane copolymer having a meltindex of 1.0 g./10 min. and a density of 0.918 g/cc. (DFDC 7087). Thecore layer may be a single layer or multiple layers of at least 3 layersor more; the fourth (4) being another interposed layer of the samecomposition as the second layer and the fifth layer (5) being the innersealant layer described above. The first outer sealant layer and thefifth sealant layer each comprise about 10-30% of the thickness of themultilayer film. The intermediate layers (second and fourth layers)comprise about 5-20% of the thickness of the multilayer film and thecore layer comprises about 30-50% of the thickness of the multilayerfilm. The total layer of the multilayer film is about 1-5 mils inthickness, preferably 1-2.5 mils in thickness and more preferably 1-2.0mils in thickness.

It was found that by using the preferred ethylene/α-olefin interpolymerin the inner and outer sealant layers significantly improved impactresistance and bag drop performance, particularly under cold conditionsresulted in comparison to conventional bags formed with multilayer filmsthat did not have the preferred ethylene/α-olefin interpolymer componentin the outer and inner sealant layers of the bag film. Also, a portionof the core can contain the preferred interpolymer for performanceimprovement. Improved results were noted when the preferred interpolymerwas used in the optional interposed layer in the bag film. Themultilayer film of this invention is a clear film that runs well on bagforming machines and is particularly desired, for example, for makingmilk bags in the 1-6 gallon size range.

The Outer and Inner Sealant Lavers

In one embodiment, the multi-layer film comprises at least one outersealant layer and at least one inner sealant layer. The outer sealantlayer is externally on one side of the multi-layer film, and the innersealant layer is externally on the other side of the multi-layer film.The outer and inner sealing layers can comprise more than one layer offilm, for example, 2, 3, 4 or more layers of film. The thicknesses ofthe outer and inner sealing layers are usually the same but can havedifferent thicknesses.

The outer and inner sealant layers can comprise about 10-100% by weightof the preferred ethylene/α-olefin interpolymer and can contain up to90% by weight of a polymer of ultralow density polyethylene (ULDPE),ethylene/octene -1 copolymer having a density in the range of about0.910 to 0.914 g/cc and a melt index of about 0.7 to 1.0 g/10 min. or alinear low density polyethylene (LLDPE), ethylene/octene-1 copolymerhaving a density in the range of about 0.917 to 0.925 g/cc and a meltindex of about 0.7 to 1.0 g/10 min. One useful sealing layer comprisesabout 75-90% by weight of an ultralow density polyethylene (ULDPE)having a density in the range of about 0.911 to 0.913 g/cc and a meltindex of about 0.8 to 0.9 g/10 min and 10-25% by weight of a linear lowdensity polyethylene (LLDPE), ethylene /octene-1 copolymer having adensity in the range of about 0.918 to 0.922 g/cc and a melt index ofabout 0.8 to 0.9 g/10 min. The inner and outer sealing layers preferablyhave the same polymeric constituents in the same ratios but can containvariations of the polymeric constituents, for example, variations ofdensity and melt index in the above ranges and the polymericconstituents can have different ratios.

For this invention, the thickness of each of the sealing layers and saidat least one outer is from about 1% to about 20% of the total thicknessof the multi-layer film. In other embodiments of the invention, thetotal combined thickness of the sealant layers can be about 11%, about12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%,about 19%, about 20% of the total thickness of the multi-layer film. Thetotal combined thickness of the sealing layers can also be intermediatepercentage between the percentages cited , supra, for example, a totalcombined thickness that is from about 11.1%, 11.2%, 11.3%, 11.4%, etc.between other percentages cited.

The First and the Second Interposed Layers

The interposed layer is optional. In one embodiment, the multi-layerfilm comprises a first interposed layer adjacent to an outer sealantlayer and adjacent to the core layer and on the other side of the corelayer, a second interposed layer is adjacent to the core layer andadjacent to the inner sealant layer. The inner sealant layer isexternally on one side of the multi-layer film, and the outer sealantlayer is externally on the other side of the multi-layer film.

The multi-layer film comprises one first interposed layer or more thanone interposed layer. For example, the multi-layer film can have two,three, or four interposed layers stacked adjacent to each other.Similarly, the multi-layer film comprises one second interposed layer ormore than one second interposed layer.

While it may be preferred that the first interposed layer and the secondinterposed layer thicknesses are approximately the same, in otherpreferred embodiments, their thicknesses may vary and not be the same.

Also, while it is preferred that the multi-layer film of the presentinvention comprises the same number of first interposed layers and thesecond interposed layers, in other embodiments, the number of firstinterposed layers may be different from the number of second interposedlayers.

The first or the second at least one interposed layers preferablycomprises the preferred ethylene/α-olefin interpolymer Other usefulinterpolymers can have a density of from about 0.910 to about 0.917,preferably, 0.915 to and a melt-index of about 0.7 to 1.0, preferably,0.915 g/10 min. The density range can also be defined by any two numbersfrom about 0.910 to about 0.912, about 0.913 to about 0.914, about 0.916to about 0.917 g/cc and the like. Similarly, the melt-index range can bedefined by any two numbers from about 0.5 to about 0.90 g/10 min.

For this invention, the total combined thickness of said first at leastone interposed layer and said second at least one interposed layer isfrom about 1% to about 20% of the total thickness of the multi-layerfilm. In a preferred embodiment, the thickness of said at least oneinterposed layer is from about 1% of the total multilayer to about 19%of the total multilayer film thickness. The thickness of each of theinterposed layers can be the same or each layer can vary, e.g., a layercan be about 3% and the second 17%, or 4-16%, 9-11% and the like.

Core Layer

The multi-layer film comprises at least one core layer that is adjacentto the first at least interposed layer on one side and the second atleast one interposed layer on the opposite side. If an interposed layeris not used in the multilayer film, the core layer is adjacent to thesealant layer. The core layer comprises a polymer or a polymer blend ofabout 0-100% by weight or preferably of about 30-70% by weight of ormore preferably 30-50% by weight of a linear low density polyethylene(LLDPE) of ethylene/octene-1 copolymer having a density of about 0.910to 0.920 g/cc and melt index of about 0.8 to 1.2 g/10 min. and 0-100% byweight of a linear low density butene polyethylene (LLDPE) or lowdensity hexene poyethylene having a density of about 0.918 to 0.930 g/ccand a melt index of about 0.8 to 1.2 g/10 min or preferably of 70-30% byweight of or more preferably 50-70% by weight of the linear low densitybutene polyethylene or linear low density hexene polyethylene.. Morepreferably, the polymer blend of the core layer comprises blend of about35-45% by weight of a linear low density polyethylene (LLDPE) having adensity of about 0.914 to 0.918 g/cc and a melt index of about 0.9 to1.1 g/10 min and 55-65% by weight of a linear low density butenepolyethylene (LLDPE) having a density of about 0.918 to 0.920 and a meltindex of about 0.9 to 1.1 g/10 min. Depending on the product and theconditions under which the product is stored, shipped and used, the corelayer can contain up to 100% by weight of the preferred ethylene/a-olefin interpolymer. The percentage of the interpolymer can vary from5, 10, 20, 30, 40, 50, 60, 70, 80 and 90% and any amounts betweendepending on the properties required for the multilayer film.

The core layer preferably is a single layer but can be a multilayercomponent each layer having the same or similar polymer blend within theabove ranges. The thickness of the core layer can comprise about 30-50%of the total thickness of the multilayer film.

The present invention also is directed to a pouch containing a flowablematerial, said pouch being made from the previously describedmulti-layer film in tubular form and having transversely heat sealedends.

The present invention is further directed to a process for makingpouches filled with a flowable material, using a conventional bag makingprocess describe hereinafter; Also, pouches can be made using a verticalform, fill and seal (“VFFS”) apparatus, in which each pouch is made froma flat web of film by forming a tubular film therefrom with alongitudinal seal and subsequently flattening the tubular film at afirst position and transversely heat sealing said tubular film at theflattened position, filling the tubular film with a predeterminedquantity of flowable material above said first position, flattening thetubular film above the predetermined quantity of flowable material at asecond position and transversely heat sealing said tubular film at thesecond position, the improvement comprising making the pouches from aflat web of a film made from a multilayer film described previously. TheVFFS processes and its modifications are described in U.S. Pat. No. US5,538,590, US 9,327,856 and US 9,440,757 and are incorporated byreference herein in their entirety.

Although melt-index ranges are specified herein, it is understood thatthe polymers have melt indices typical of film-grade polymers can beused. The multi-layer films of the present invention have the ability toform a lap seal as well as a fin seal. They also substantially reducethe curl in the laminate.

One preferred method of manufacturing film is the so-called blown filmprocess. The film, after manufacture, is slit longitudinally intoappropriate widths. The preferred method of manufacture of a multilayerfilm is by using a blown film co-extrusion process, although othermethods of manufacture of the film may be used.

The multilayer film of the invention is particularly useful in theformation of bags that may be used in the packaging of flowablematerials, for example, liquids, as defined above. In particular, thebags are used in the packaging of refrigerated liquids in particular,milk.

Other Additives

It will be understood by those skilled in the art that additives such asantioxidants, stabilizers, anti-block agents, and slip additives, may beadded to the polymers from which bags of the present invention are made.Optionally, the inner sealant layer, the outer sealant, the interposedlayer may further comprise one or several additives useful to makeeasier the processing of a film in a bag making process, such as, forexample, polymer processing aid concentrate, and/or slip/anti-blockconcentrates. Any of such additives well known to person skilled in theart can be used. Advantageously, the following additives are preferred.

Slip Agents

The range of the slip agents that can be used is from about 200 to 2000ppm or 0.5-2.5% by weight of the sealing layer. A preferred slip agentis erucamide or other fatty acid amide, such as, oleamide. The slipagent lowers the coefficient friction of the film and allows it to slidereadily over various surfaces.

Anti-Blocking Agents

Any film anti-blocking agent well known to skilled workman maybe addedto the film layers in the range of about 1000-5000 ppm or 0.5-2.5% byweight of the sealant layer. Typical anti-blocking agents, such as,diatomaceous earth, synthetic silica or talc can be added to the innerand outer sealant layers of the film. The anti-blocking material isparticularly useful in reducing the coefficient of friction between thefilm and the metallic surfaces over which the film is drawn during thebag making process.

Processing Aid

Any processing aid well known to skilled workman, preferably and notlimited to fluoro-elastomer based polymer may be added to outer andinner sealing layers of the film.

Bag-Making Processes

This invention also relates to a process for making bags that arefillable with flowable material, using a bag line, wherein each bag ismade from a flat web of film by the following steps:

-   (I) Unwinding film from two rolls top and two rolls bottom.-   (II) Ink jet code labeling each bag.-   (III) Punching spout hole in each bag.-   (IV) Inserting spout into bag.-   (V) Brush bag to remove entrapped air.-   (VI) Cross seals formed on bottom of one bag and top of next bag.-   (VII) Bags pulled through line with servo drive.-   (VIII) Perforations formed between adjacent cross seals.-   (IX) Bags pushed to end of line via conveyor belt.-   (X) Bags packed into boxes.

The above steps are typical for a bag making machine. It should be notedthat the order of the steps can be changed depending on the bag-makingmachine.

Experimental

In the present set of experiments, generally, a multi-layer film is madeusing film extrusion processes that are well-known to the filmmanufacturing industry. The multi-layer film is extruded on aconventional extrusion line for multilayer films such as a three-layer,five layer, seven layer, nine layer or more blown-film co-extrusionline. Films from the resin compositions of this invention can also bemade using other film extrusion processes which are well-known to thefilm manufacturing industry.

To prepare the multilayer films of the following Examples, the followingoperating conditions were used: line throughput -- 350 lbs./hour; blowup ration- 2.5; lay-flat -38.65 inches;rolls double wound 2-up@16.75inches width; each roll OD (outside diameter) 9.5 inches except for oneset of rolls at 8.25 inches OD; dies size 250 mm; die gap 2 mils; airring and IBC cooling @ 50° F. using air cooled by chilled water;rotating nip at carouse; auto gauge control; treaters OFF. The resultingfilm thickness is 1.8 mils.

Dairy bags made for testing: 2.5 gallon bag; production rate of 25 bagsper minute; two ply bag where edges of bag heat sealed together usingimpulse sealing; 15.75 inch wide inside of seal to seal inside of seal;18.00 inch long inside of seal to inside of seal; and dairy spout andcap.

Bruceton Stair Drop Test (version of ASTM D 5276 A 2.4.2)

The Bruceton Stair test requires 30 well-made bags. The first bag ispositioned with the longitudinal axis of the bag coincident with animaginary horizontal line, the bottom surface of the bag at a suitableinitial drop height, say 8 feet, and the vertical seal facing upwards.In this orientation, the bag is dropped onto a stainless steel sheet,and then inspected visually and tactilely for leakers. The test isconducted by maintaining the bag temperature at about 4° C.

If the first bag survives the drop test intact without leaking water,then a new bag is selected and dropped from a height of an additional 1foot, that is, 9 feet. On the other hand, if the first bag has developeda leak, then a new bag is selected and dropped from a height, which islower by 1 foot, that is, 7 feet. The testing continues, using a new bagfor every drop, until at least 5 passes and 5 failures have occurred inthe height range where both passes and failures are occurring. The 50%failure height is then calculated using the statistical method of ASTM1D 5628.

Abbreviations used in Examples:

-   Dow “Elite″ AT 6401 ULDPE, ethylene/octene -1 copolymer, melt index    0.85 g/10 min., density 0.912 g/cc.-   Dow “Elite” 5400 G - LLDPE, ethylene/octene copolymer, melt index    1.0 g/10 min.. density 0.916 g/cc.-   Dow XUS59900. 100 - LLDPE, ethylene/octene -1 copolymer, melt index    0.85 g/10 g/min., density 0.920 g/cc.-   Dow “Innate” XUS 59910.04 (16C181 R01) interpolymer of    ethylene/octene- 1 copolymer and a second ethylene/ α-olefin    copolymer, melt index 0.85 g/10 min. density 0.915 g/cc.-   DFDC 7087 - LLDPE ethylene butene copolymer, melt index 1.0 g/10    min. density 0.918 g/cc.-   Ampacet 10090 Slip Agent - carrier resin LDPE, density 0.92 g/cc,    additive 5% erucamide.-   Ampacet10063 Anti Block Agent- carrier resin LDPE, density 0.92    g/cc, anti-block additive 20%.

The following examples illustrate the invention.

Example 1

The following films were formed utilizing the extruder and extrusionconditions previously described.

Benchmark Structure is an industry standard having a thickness of 2.2mils of a monolayer structure of 7 multiple layers comprising 37% byweight of (Dow “Elite″5400 G), LLDPE, ethylene octene copolymer, 60%(DFDC 7087) LLDPE, ethylene butane copolymer and 1.5% Ampacet Slip agentLDPE carrier resin and anti-block slip agent.

Multilayer Film Structure 3 is a multilayer structure having a thicknessof 1.8 mils and comprises:

-   (1) an outer and an inner sealant layer comprising 97% by weight of    (Dow “Innate” XUS 59910.04) the preferred ethylene/-α olefin    interpolymer having melt index of 0.85 g/10 min. and density of    0.915 g/cc. and 1.5% by weight of Ampacet 10090 Slip Agent and 1.5%    by weight of Ampacet Anti Block Agent-   (2) a core layer of multiple of 5 layers of 98.5 % by weight of    (“Elite” 5400) LLDPE, ethylene/octene -1 copolymer and 1.5% by    weight of Ampacet 10090 Slip Agent.

Multi-layer Film Structure 4 having a thickness of 1.8 mils andcomprises:

-   (1) an inner and an outer sealant layer comprising 97% by weight    (Dow “Innate” XUS 59910.04) the preferred ethylene/-α olefin    interpolymer and 1.5% by weight of Ampacet 10090 Slip Agent and 1.5%    by weight of Ampacet Anti Block Agent and-   (2) a core layer of multiple 5 layers comprising 38.5 % by weight    ('`Elite″ 5400G) LLDPE, ethytene/octene -1 copolymer and 60.0% by    weight of (DFDP 7087) LLDPE, ethylene butane copolymer having a melt    index of 1.0 g/10 min. and a density of 0.918 g/cc. and 1.5% by    weight of Ampacet 10090 Slip Agent.

Multilayer Film Structure 9 having a thickness of 1.8 mils andcomprises:

-   [0074] 1) an inner and an outer sealant layer comprising 83% by    weight of (“Elite AT 6401) ULDPE, ethylene/octene -1 copolymer    having a melt index of 0.85 g/10 min. and density of 0.912 g/cc. and    14.0% by weight of (XUS 59900.100) LLDPE, ethylene/octene-1    copolymer having a melt index of 0.85 g/10 min. and density of 0.920    g/cc and 1.5% by weight of Ampacet 10090 Slip Agent and 1.5% by    weight of Ampacet Anti Block Agent and;-   [0075] 2) an interposed layer comprising 98.5% of (Dow “Innate''XUS    59910.04) the preferred ethylene/-α olefin interpolymer and 1.5 % by    weight of Ampacet 10090 Slip Agent;-   [0076] 3) a core layer of multiple 3 layers comprising 38.5 % by    weight of (“Elite 5400G) LLDPE, ethylene/octene -1 copolymer having    a melt index of 1.0 g/10 min. and density of 0.916 g/cc. and 60.0%    by weight of (DFDC 7087) LLDPE, ethylene butene copolymer having a    melt index of 1.0 g./10 min. and a density of 0.918 g/cc and 1.5% by    weight of Ampacent 10090 Slip Agent.

Each of the above prepared film structures ... Benchmark Structure,Structure 3, Structure 4, and Structure 9 were formed into bags fortesting. 2.5 gallon dairy bags were formed as described above and filedwith water and refrigerated to a temperature of about 4° C. and the bagswere subjected to the Bruceton Stair Drop Test as described above. Also,bags were tested at ambient temperatures. The following are the testresults of the test:

TABLE 1 Bruceton Stair Drop Test Data F0 F0 F0 F50 F50 F100 F100 FilmStructure Film Thickness (Mils) Temp. Ambient Feet Temp. 4° C. FeetTemp. Ambient Feet Temp. 4° C. Feet Temp. Ambient Feet Temp. 4° C. FeetBenchmark 2.2 2.0 1.0 3.8 2.3 5.0 4.0 Structure 3 1.8 3.0 3.0 4.6 5.07.0 7.0 Structure 4 1.8 - 4.0 - 5.8 Structure 9 1.8 3.0 3.0 4.7 5.2 6.07.0

Example 2

Bags formed from film Structure 3 were filled at a major dairy customerwith a refrigerated ice cream mixture. 6000 bags, 2.5 gallons size, werefilled on a Liqui-Box Orbiter 6000 C6T-0 filler. A second 6000 bagsformed from film Structure 9 were filled on the same equipment with arefrigerated ice cream product. No problems were encountered duringfilling of the bags and there were no problems in shipping anddistribution of the bags and no problems were reported by the end usersof these dairy product filled bags.

4800 2.5 gallon size bags of film Structure 9 were filled with arefrigerated diary product (ice cream) on a Liqui-Box 1500-CITPacesetter III and bag loading system and loaded into boxes. No problemswere encountered during filling of the bags and there were no problemsin shipping and distribution of the bags and no problems were reportedby the end users of these dairy product filled bags.

1. A multilayer film for making pouches containing flowable materials,said multi-layer film comprising the following layers in order, from anat least one inner sealant-layer to at least one core layer and to an atleast one outer sealant-layer for packaging liquids comprising: (A) atleast one outer sealant layer and at least one inner sealant layer, eachlayer comprising an ainterpolymer composition comprises from 50-75% byweight of a first ethylene/a-olefin copolymer fraction having a densityin the range of 0.894 to 0.908 g/cc; a melt index in the range of 0.2 to1 g/10 min.; and from 25 to 50 percent by weight of a secondethylene,a-olefin copolymer fraction and wherein the interpolymer has adensity in the range of 0.910 to 0.924 g/cc and a melt index in therange from 0.5 to 2 g/10 min: a zero shear viscosity ratio (ZSVR) in therange of from 1.15 to 2.5; a molecular weight distribution, expressed asthe ratio of the weight average molecular weight (Mw/Mn), in the rangeof 2.0 to 4.0; (B) at least one core layer selected from the groupconsisting of: (1) a core layer comprising linear low densitypolyethylene, ethylene/octene-1 copolymer having a melt index of 1.0g/10 min. and a density of 0.916 g/cc: (2) a core layer comprising30-100% by weight of linear low density polyethylene, ethylene/octene -1copolymer having a melt index of 1.0 g/10 min. and a density of 0.916g/cc and 70-0% of ethylene butane copolymer having a melt index of 1.0g/10 min and a density of 0.918; and (3) a core layer comprising 30-100%by weight of linear low density polyethylene, ethylene/hexene -1copolymer having a melt index of 1.0 g/10 min. and density of 0.916g/cc. and 70-0% by weight of a linear low density ethylene/hexenecopolymer having a melt index of 1.0 g/10 min. and a density of 0.918g/cc .
 2. The multilayer film of claim 1 wherein the at least one outersealant layer, the at least one inner sealant layer and the core layerindividually comprise a single layer up to and including eight layers.3. The multilayer film of claim 2 wherein the ethylene/a-olefininterpolymer comprises a polymer fraction of linear low densitypolyethylene and a second copolymer fraction of ethylene/octene- 1copolymer and the interpolymer having a density of 0.915 g/cc and a meltindex of 0.85 g/10 min.
 4. The multilayer film of claim 3 wherein the atleast one core layer comprises a linear low density polyethylene,ethylene/octene-1 copolymer having a melt index of 1.0 g/10 min. and adensity of 0.91 6 g/cc.
 5. The multilayer film of claim 3 wherein the atleast one core layer comprises 30-100% by weight of ethylene/octene -1copolymer having a melt index of 1.0 g/10 min. and a density of 0.916g/cc and 70-0% of ethylene butane copolymer having a melt index of 1.0g/10 min and a density of 0.918 and the copolymers are in a ratio of40/60.
 6. The multilayer film of claim 3 wherein the at least one corelayer comprises 30-100% by weight of ethylene/hexene -1 copolymer havinga melt index of 1.0 g/10 min. and density of 0.916 g/cc. and 70-0% byweight of ethylene/hexene copolymer having a melt index of 1.0 g/10 min.and a density of 0.918 g/cc and the copolymers are a weight ratio of40/60.
 7. A multilayer film for making pouches containing flowablematerials, said multi-layer film comprising the following layers inorder, from an at least one inner sealant-layer to an at least oneinterposed layer to an at least one core layer to a second interposedlayer and to an outer sealant-layer for packaging liquids comprising:(A) at least one outer sealant layer and at least one inner sealantlayer, each layer comprising an ultra-low density polyethylene, ethylene/octene-1 copolymer having a melt index of 0.85 g/10 min and a densityof 0.912 g/cc. and an ethylene/a-olefin interpolymer compositioncomprising linear low density polyethylene, ethylene /octene -1copolymer having a melt index of 0.85 g/10 min.ad a density of 0.920g/cc; (B) at least one interposed layer position between the at leastone core layer and the at least on outer sealant layer and the at leastone second interposed layer between the at least one core layer and thesecond outer sealant layer comprising an ethylene/a-olefin interpolymercomposition comprises from 50-75% by weight of a first ethylene/a-olefincopolymer fraction having a density in the range of 0.894 to 0.908 g/cc:a melt index in the range of 0.2 to 1 g/10 min.; and from 25 to 50percent by weight of a second ethylene/a-olefin copolymer fraction andwherein the interpolymer has a density in the range of 0.910 to 0.924g/cc and a melt index in the range from 0.5 to 2 g/10 min; a zero shearviscosity ratio (ZSVR) in the range of from 1.15 to 2.5: a molecularweight distribution, expressed as the ratio of the weight averagemolecular weight (Mw/Mn), in the range of 2.0 to 4.0; (C) at least onecore layer selected from the group consisting of (1) a core layercomprising linear low density polyethylene, ethylene/octene-1 copolymerhaving a melt index of 1.0 g/10 min. and a density of 0.916 g/cc; (2) acore layer comprising 30-100% by weight of linear low densitypolyethylene, ethylene/octene -1 copolymer having a melt index of 1.0g/10 min. and a density of 0.916 g/cc and 70-0% of ethylene butanecopolymer having a melt index of 1.0 g/10 min and a density of (0.918;and (3) a core layer comprising 30-100% by weight of linear low densitypolyethylene, ethylene/hexene -1 copolymer having a melt index of 1.0g/10 min. and density of 0.916 g/cc. and 70-0% by weight of linear lowdensity polyethylene, ethylene/hexene copolymer having a melt index of1.0 g/10 min. and a density of 0.918 g/cc .
 8. The multilayer film ofclaim 7 wherein the at least one outer sealant layer, the at least oneinner sealant layer, the core layer and the interposed layers betweenthe sealant layers and the core layer individually comprise a singlelayer up to and including eight layers.
 9. The multilayer film of claim7 wherein the at least one core layer comprises 30-100% by weight oflinear low density polyethylene, ethylene/octene -1 copolymer having amelt index of 1.0 g/10 min. and a density of 0.916 g/cc and 70-0% ofethylene butane copolymer having a melt index of 1.0 g/10 min and adensity of 0.918 in a weight ratio of 40/60.
 10. The multilayer film ofclaim 7 wherein the at least one core layer comprises 30-100% by weightof linear low density polyethylene, ethylene/hexene -1 copolymer havinga melt index of 1.0 g/10 min. and density of 0.916 g/cc. and 70-0% byweight of linear low density polyethylene, ethylene/hexene copolymerhaving a melt index of 1.0 g/10 min. and a density of 0.918 g/cc in aweight ratio of 40/60.
 11. A bag for containing flowable liquid formedof the multilayer film of claim
 1. 12. The bag of claim 11 wherein theflowable material is a refrigerated dairy product.
 13. A bag forcontaining flowable liquid formed of the multilayer film of claim
 7. 14.The bag of claim 13 wherein the flowable material is a refrigerateddairy product.
 15. A process for filling bags with flowable productwherein the bags are formed from the multilayer film of claim
 1. 16. Aprocess for filling bags with flowable product wherein the bags areformed from the multilayer film of claim 7.